JP6111992B2 - Developer cartridge - Google Patents

Description

  The present invention relates to a developing cartridge mounted on an image forming apparatus employing an electrophotographic system.

  As a developing cartridge to be mounted on an electrophotographic image forming apparatus, for example, it has a developing roller carrying toner and is configured to be mounted on the image forming apparatus in a state where it is mounted on a drum cartridge having a photosensitive drum. Developer cartridges are known.

  As such a developing cartridge, a developing cartridge including a coupling gear that receives a driving force from a main body casing and transmits the driving force to a developing roller is known (for example, see Patent Document 1 below).

JP 2009-294484 A

  In the developing cartridge described in Patent Document 1 described above, since the inner diameter of the coupling portion of the coupling gear is small, it may be difficult to rotate the coupling gear, for example, when the torque of the developing roller increases.

  In this case, in order to rotate the coupling gear, it is necessary to input a larger driving force from the main body casing to the coupling gear.

  However, if the driving force from the main casing is increased, the coupling gear may be damaged.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing cartridge that can efficiently transmit a driving force from an external driving source to a developer carrying member while suppressing damage to a passive member.

(1) In order to achieve the above-described object, the developing cartridge of the present invention is configured to support a developer that is rotatably supported by the casing configured to accommodate the developer. And a passive member configured to transmit a driving force from an external driving source to the developer carrier, and configured to rotate about an axis along the rotation axis of the developer carrier. And a cylindrical passive member.

  The housing includes a support portion that rotatably supports the passive member.

  The passive member extends along the radial direction of the passive member and is configured to receive a driving force from an external driving source, and to transmit the driving force received by the receiving portion to the developer carrier. A transmission portion configured to be disposed on the outer peripheral surface of the passive member, and a cylindrical shape that is disposed inward of the transmission portion in the radial direction of the passive member and is fitted to the support portion so as to be relatively rotatable. A fitting portion.

  The radially outer end of the receiving portion is located radially inward of the transmitting portion and is located radially outward of the fitting portion.

  According to such a structure, a receiving part can be arrange | positioned between the fitting part fitted to a support part and a transmission part in the radial direction of a passive member.

  Here, the fitting portion has high rigidity so as to stably rotate the passive member. Further, the transmission unit has high rigidity so as to reliably transmit the driving force.

  Therefore, the rigidity of the whole passive member is securable by arrange | positioning a receiving part between the fitting part and transmission part which have such high rigidity.

  Thus, even when a large driving force is input from the external driving source to the receiving portion, the driving force can be stably received.

As a result, it is possible to efficiently transmit the driving force from the external driving source to the developer carrying member while suppressing the damage of the passive member.
(2) The rotation radius of the transmission part may be twice or more the radial dimension of the receiving part.

According to such a structure, a receiving part can be arrange | positioned sufficiently away from the rotation center of a passive member, and the driving force received by the receiving part can be efficiently transmitted to a transmission part.
(3) The passive member may overlap the developer carrier when projected in the direction in which the rotation axis extends.

According to such a structure, a passive member can be arrange | positioned efficiently.
(4) The outer periphery of the support portion may be located radially outward from the radially inner end of the receiving portion.

  According to such a structure, a support part can be arrange | positioned so that it may overlap with a receiving part when it sees in an axial direction.

  Therefore, the diameter of the support portion can be made larger than the diameter of the passive member, and the rigidity of the support portion can be ensured.

As a result, the passive member can be rotated more stably.
(5) The passive member may have a gap between the fitting portion and the transmission portion.

According to such a structure, a fitting part and a transmission part can be comprised separately, and a fitting part and a transmission part can be shape | molded accurately.
(6) The transmission unit may have gear teeth.

  According to such a configuration, the driving force can be transmitted with a simple configuration.

  The developing cartridge of the present invention can efficiently transmit the driving force from the external driving source to the developer carrying member while suppressing damage to the passive member.

FIG. 1 is a central sectional view showing a developing cartridge of the present invention. FIG. 2 is a central sectional view of a printer to which the developing cartridge shown in FIG. 1 is mounted. 3 is a perspective view of the developing cartridge shown in FIG. 1 as viewed from the left rear. In FIG. 3, the gear cover is omitted to show the gear train. FIG. 4 is a left side view of the developing cartridge shown in FIG. FIG. 5 shows a state where the developing coupling is removed from the developing cartridge shown in FIG. FIG. 6A is a left side view of the development coupling shown in FIG. 6B is a right side view of the development coupling shown in FIG. FIG. 7A is a cross-sectional view taken along line AA of the development coupling shown in FIG. 6A. FIG. 7B is a cross-sectional view of the development coupling shown in FIG. 6A along BB. FIG. 8 is a perspective view of the main body coupling viewed from the lower right.

1. Overview of Developing Cartridge As shown in FIG. 1, the developing cartridge 1 includes a developing roller 2 as an example of a developer carrier, a supply roller 3, a layer thickness regulating blade 4, and a toner container 5. .

  In the following description, when referring to the direction of the developing cartridge 1, the state in which the developing cartridge 1 is horizontally placed is used as the upper and lower reference. That is, the upper side in FIG. 1 is the upper side, and the lower side in the paper is the lower side. Further, the right side of FIG. 1 is the front, and the left side of FIG. 1 is the rear. In addition, when the developing cartridge 1 is viewed from the front, the left and right reference is used. That is, the front side of the page of FIG. 1 is the left side, and the back side of the page is the right side.

  The developing roller 2 is rotatably supported at the rear end portion of the developing cartridge 1. The developing roller 2 includes a developing roller shaft 2A and a developing roller body 2B.

  The developing roller shaft 2A has a substantially cylindrical shape. The developing roller shaft 2A extends in the left-right direction. The developing roller shaft 2A is made of metal.

  The developing roller body 2B has a substantially cylindrical shape. The developing roller body 2B extends in the left-right direction. The developing roller body 2B is made of conductive rubber. The developing roller body 2B does not cover the left and right ends of the developing roller shaft 2A, but covers the substantially horizontal center of the developing roller shaft 2A.

  The supply roller 3 is disposed on the front lower side of the developing roller 2. The supply roller 3 is rotatably supported by the developing cartridge 1. The supply roller 3 includes a supply roller shaft 3A and a supply roller body 3B.

  The supply roller shaft 3A has a substantially cylindrical shape. The supply roller shaft 3A extends in the left-right direction. The supply roller shaft 3A is made of metal.

  The supply roller main body 3B has a substantially cylindrical shape. The supply roller main body 3B extends in the left-right direction. The supply roller body 3B is made of a conductive sponge. The supply roller main body 3B does not cover the left and right end portions of the supply roller shaft 3A, but covers the substantially center in the left-right direction of the supply roller shaft 3A. The supply roller main body 3B is in contact with the front lower end portion of the developing roller main body 2B.

  The layer thickness regulating blade 4 is disposed on the front upper side of the developing roller 2. The layer thickness regulating blade 4 is in contact with the front end portion of the developing roller 2.

  The toner container 5 is disposed in front of the supply roller 3 and the layer thickness regulating blade 4. The toner storage unit 5 is configured to store toner as an example of a developer. The toner storage unit 5 includes an agitator 6.

The agitator 6 is rotatably supported in the toner storage unit 5.
2. Use Mode of Developer Cartridge As shown in FIG. 2, the developer cartridge 1 is mounted on an image forming apparatus 11 and used.

  The image forming apparatus 11 is an electrophotographic monochrome printer. The image forming apparatus 11 includes an apparatus body 12 as an example of the outside, a process cartridge 13, a scanner unit 14, and a fixing unit 15.

  The apparatus main body 12 is formed in a substantially box shape. The apparatus body 12 includes an opening 16, a front cover 17, a paper feed tray 18, and a paper discharge tray 19.

  The opening 16 is disposed at the front end of the apparatus main body 12. The opening 16 communicates the inside and outside of the apparatus main body 12 in the front-rear direction so as to allow passage of the process cartridge 13.

  The front cover 17 is disposed at the front end of the apparatus main body 12. The front cover 17 has a substantially flat plate shape. The front cover 17 extends in the vertical direction, and is swingably supported on the front wall of the apparatus main body 12 with the lower end portion as a fulcrum. The front cover 17 is configured to open or close the opening 16.

  The paper feed tray 18 is disposed at the bottom of the apparatus main body 12. The paper feed tray 18 is configured to accommodate the paper P.

  The paper discharge tray 19 is disposed on the front half of the upper wall of the apparatus body 12. The paper discharge tray 19 is recessed downward from the upper surface of the apparatus main body 12 so that the paper P is placed thereon.

  The process cartridge 13 is accommodated in the substantially vertical center of the apparatus main body 12. The process cartridge 13 is configured to be attached to or detached from the apparatus main body 12. The process cartridge 13 includes a drum cartridge 20 and a developing cartridge 1.

  The drum cartridge 20 includes a photosensitive drum 21, a scorotron charger 22, and a transfer roller 23.

  The photosensitive drum 21 is rotatably supported at the rear end portion of the drum cartridge 20.

  The scorotron charger 22 is disposed behind the photosensitive drum 21 and spaced from the photosensitive drum 21.

  The transfer roller 23 is disposed below the photosensitive drum 21. The transfer roller 23 is in contact with the lower end portion of the photosensitive drum 21.

  The developing cartridge 1 is mounted on the drum cartridge 20 in front of the photosensitive drum 21 so that the developing roller 2 contacts the front lower end portion of the photosensitive drum 21.

  The scanner unit 14 is disposed above the process cartridge 13. The scanner unit 14 is configured to emit a laser beam based on image data toward the photosensitive drum 21.

  The fixing unit 15 is disposed behind the process cartridge 13. The fixing unit 15 includes a heating roller 24 and a pressure roller 25 that is pressed against the rear upper end of the heating roller 24.

  When the image forming apparatus 11 starts an image forming operation, the scorotron charger 22 uniformly charges the surface of the photosensitive drum 21. The scanner unit 14 exposes the surface of the photosensitive drum 21. Thereby, an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 21.

  The agitator 6 agitates the toner in the toner storage unit 5 and supplies it to the supply roller 3. The supply roller 3 supplies the toner supplied from the agitator 6 to the developing roller 2. At this time, the toner is frictionally charged positively between the developing roller 2 and the supply roller 3 and is carried on the developing roller 2. The layer thickness regulating blade 4 regulates the layer thickness of the toner carried on the developing roller 2 to a constant thickness.

  Then, the toner carried on the developing roller 2 is supplied to the electrostatic latent image on the surface of the photosensitive drum 21. As a result, the toner image is carried on the surface of the photosensitive drum 21.

  The paper P is fed from the paper feed tray 18 between the photosensitive drum 21 and the transfer roller 23 one by one at a predetermined timing by the rotation of various rollers. The toner image on the surface of the photosensitive drum 21 is transferred to the paper P when the paper P passes between the photosensitive drum 21 and the transfer roller 23.

Thereafter, the sheet P is heated and pressed when passing between the heating roller 24 and the pressure roller 25. As a result, the toner image on the paper P is thermally fixed to the paper P. Thereafter, the paper P is discharged to the paper discharge tray 19.
3. Details of Developing Cartridge As shown in FIG. 3, the developing cartridge 1 includes a developing frame 31 as an example of a housing and a gear train 33.
(1) Development frame The development frame 31 has a substantially box shape. The developing frame 31 includes a pair of side walls 35, a lower wall 36, a front wall 37, an upper wall 38, and a bearing member 32.

  Each of the pair of side walls 35 is disposed at each of both end portions of the developing frame 31 in the left-right direction. Each of the pair of side walls 35 has a substantially rectangular flat plate shape in side view extending in the front-rear direction.

  The lower wall 36 has a substantially flat plate shape extending in the front-rear direction. The left and right ends of the lower wall 36 are continuous with the lower ends of the pair of side walls 35.

  The front wall 37 extends upward continuously from the front end of the lower wall 36. The front wall 37 has a substantially rectangular flat plate shape when viewed from the front. The left and right ends of the front wall 37 are continuous with the front ends of the pair of side walls 35.

  The upper wall 38 has a flat plate shape that is substantially rectangular in plan view. The front end portion of the upper wall 38 is continuous with the upper end portion of the upper wall 38. The left and right ends of the upper wall 38 are continuous with the upper ends of the pair of side walls 35.

  As shown in FIG. 5, the bearing member 32 is supported by the front end portion of the left side wall 35. The bearing member 32 has a substantially rectangular flat plate shape in side view. The bearing member 32 rotatably supports the developing roller shaft 2A at the rear end portion, and rotatably supports the supply roller shaft 3A at the lower end portion. The bearing member 32 has a coupling support boss 39 as an example of a support portion.

The coupling support boss 39 is disposed at the front upper end portion of the bearing member 32. The coupling support boss 39 has a substantially cylindrical shape protruding leftward from the left surface of the bearing member 32.
(2) Gear Train The gear train 33 is disposed on the left side of the developing frame 31 at the left end of the developing cartridge 1 as shown in FIGS. 3 and 4. The gear train 33 is covered with a gear cover (not shown). The gear train 33 includes a development coupling 41 as an example of a passive member, a development gear 42, a supply gear 43, an idle gear 44, an agitator gear 45, and a detection gear 46.

  The development coupling 41 is disposed at the front end of the development cartridge 1. The development coupling 41 has a substantially cylindrical shape extending in the left-right direction. The rear end portion of the developing coupling 41 overlaps the developing roller body 2B of the developing roller 2 when projected in the left-right direction. As shown in FIGS. 6A and 6B, the development coupling 41 includes a gear part 51 as an example of a transmission part, a fitting part 53, and a coupling part 52.

  As shown in FIGS. 6A and 7A, the gear portion 51 is disposed on the substantially right half of the development coupling 41. The gear part 51 has a substantially cylindrical shape extending in the left-right direction and closed at the left end. A central axis A of the gear portion 51 is a rotation axis of the development coupling 41. The gear part 51 has gear teeth over its entire circumference.

  The fitting part 53 is arrange | positioned in the radial direction inner side of the gear part 51, as shown to FIG. 6B and FIG. 7A. The fitting part 53 has a substantially cylindrical shape extending from the right surface of the left wall of the gear part 51 toward the right. The fitting portion 53 shares the central axis A with the gear portion 51. The outer diameter of the fitting part 53 is smaller than the inner diameter of the gear part 51. The inner diameter of the fitting portion 53 is substantially the same as the outer diameter of the coupling support boss 39. The outer peripheral surface of the fitting portion 53 is spaced from the inner peripheral surface of the gear portion 51 by a distance D. The right end portion of the fitting portion 53 protrudes to the right from the right end portion of the gear portion 51. The fitting portion 53 is fitted to the coupling support boss 39 of the developing frame 31 so as to be relatively rotatable from the radially outer side of the coupling support boss 39.

  As shown in FIGS. 6A, 7A, and 7B, the coupling portion 52 is disposed on the substantially left half of the developing coupling 41. The coupling part 52 has a substantially cylindrical shape extending leftward from the left wall of the gear part 51. The coupling part 52 shares the central axis A with the gear part 51. The outer diameter of the coupling part 52 is smaller than the outer diameter of the gear part 51. The inner diameter of the coupling part 52 is larger than the outer diameter of the fitting part 53. The coupling part 52 has a pair of engaging parts 54.

  Each of the pair of engaging portions 54 is disposed in both the radial directions of the coupling portion 52 with the central axis A of the coupling portion 52 interposed therebetween. Each of the pair of engaging portions 54 has a trapezoidal shape in a side view that bulges inward in the radial direction of the coupling portion 52 from the inner peripheral surface of the coupling portion 52 and extends in the circumferential direction of the coupling portion 52. Yes. Each of the pair of engaging portions 54 has an engaging surface 54A as an example of a receiving portion.

  The engaging surface 54A is the upstream end surface of the engaging portion 54 in the clockwise direction when viewed from the left side. The dimension S in the radial direction of the engagement surface 54 </ b> A is about ¼ of the rotation radius R of the gear portion 51. The imaginary line obtained by extending the engagement surface 54 </ b> A does not pass through the central axis A of the coupling part 52, and extends in parallel with a straight line passing through the central axis A of the coupling part 52. The imaginary lines obtained by extending the engaging surfaces 54A of the pair of engaging portions 54 are spaced from each other by an interval L. The radially outer end edge E3 of the engaging surface 54A is disposed radially inward of the outer peripheral edge E1 of the gear portion 51 and radially outward of the inner peripheral edge E2 of the fitting portion 53. The radially inner end edge E4 of the engaging surface 54A is disposed more radially inward than the inner peripheral edge E2 of the fitting portion 53. That is, the radially inner end edge E4 of the engaging surface 54A is located radially inward from the outer peripheral surface of the coupling support boss 39.

  As shown in FIGS. 3 and 4, the developing gear 42 is disposed below the developing coupling 41. The developing gear 42 has a substantially disc shape having a thickness in the left-right direction. The developing gear 42 has gear teeth over the entire circumference. The developing gear 42 is supported on the left end portion of the developing roller shaft 2A so as not to be relatively rotatable. The development gear 42 meshes with the rear lower end portion of the gear portion 51 of the development coupling 41.

  The supply gear 43 is disposed below the development coupling 41. The supply gear 43 has a substantially disk shape having a thickness in the left-right direction. The supply gear 43 has gear teeth over its entire circumference. The supply gear 43 is supported on the left end portion of the supply roller shaft 3A so as not to be relatively rotatable. The supply gear 43 meshes with the lower end portion of the gear portion 51 of the developing coupling 41.

  The idle gear 44 is disposed in front of the development coupling 41. The idle gear 44 is rotatably supported on the left side wall 35 of the developing frame 31. The idle gear 44 integrally includes a large diameter gear 44A and a small diameter gear 44B.

  The large diameter gear 44 </ b> A is disposed at the left end of the idle gear 44. The large diameter gear 44A has a substantially disc shape having a thickness in the left-right direction. The large-diameter gear 44A has gear teeth over its entire circumference. The large diameter gear 44 </ b> A meshes with the front end portion of the gear portion 51 of the development coupling 41.

  The small diameter gear 44B has a substantially cylindrical shape extending from the right surface of the large diameter gear 44A toward the right. The small diameter gear 44B shares the central axis with the large diameter gear 44A. The outer diameter of the small diameter gear 44B is smaller than the outer diameter of the large diameter gear 44A. The small diameter gear 44B has gear teeth over the entire circumference.

  The agitator gear 45 is disposed on the front lower side of the idle gear 44. The agitator gear 45 has a first gear portion 45A and a second gear portion 45B.

  The first gear portion 45 </ b> A is disposed on the right half of the agitator gear 45. 45 A of 1st gear parts have the substantially disc shape which has thickness in the left-right direction. The first gear portion 45A has gear teeth over its entire circumference. The first gear portion 45A meshes with the front end portion of the small-diameter gear 44B of the idle gear 44.

  The second gear portion 45 </ b> B is disposed on the left half of the agitator gear 45. The second gear portion 45B has a substantially disc shape having a thickness in the left-right direction so as to overlap the left surface of the first gear portion 45A. The second gear portion 45B shares the central axis with the first gear portion 45A. The outer diameter of the second gear portion 45B is smaller than the outer diameter of the first gear portion 45A. The 2nd gear part 45B has a gear tooth over the perimeter.

The detection gear 46 is disposed in front of the agitator gear 45. The detection gear 46 has a substantially disc shape having a thickness in the left-right direction. The detection gear 46 is a chipped gear that partially has gear teeth on its peripheral surface. The detection gear 46 is engaged with the second gear portion 45B of the agitator gear 45 and rotates when the unused developing cartridge 1 is first attached to the apparatus main body, and then the engagement with the second gear portion 45B is released. To be stopped. The apparatus main body 12 determines that the developing cartridge 1 is unused when the detection gear 46 detects rotation.
4). Main Body Coupling As shown in FIG. 8, the main body coupling 61 has a substantially cylindrical shape extending in the left-right direction. The main body coupling 61 is disposed on the left side of the developing cartridge 1 in the apparatus main body 12. The main body coupling 61 is retracted to the left so as to be separated from the developing cartridge 1 when the front cover 17 is opened in conjunction with opening and closing of the front cover 17 of the apparatus main body 12, and the front cover 17 is closed. Sometimes, it advances toward the developing cartridge 1 to the right. The main body coupling 61 is connected to a motor 63 as an example of a driving source in the developing cartridge 1 so as to be able to transmit driving. The main body coupling 61 includes an engaging portion 62.

  The engaging portion 62 is disposed at the right end portion of the main body coupling 61. The engaging portion 62 has a substantially cylindrical shape protruding rightward from the right end portion of the main body coupling 61. The engaging part 62 has a pair of engaging protrusions 62A.

Each of the pair of engaging protrusions 62 </ b> A has a columnar shape that is substantially rectangular in side view and extends radially outward from each of both radial surfaces of the engaging portion 62.
5. When the developer cartridge 1 is mounted on the apparatus main body 12 and the front cover 17 is closed by the operator, the main body coupling 61 advances toward the developer cartridge 1.

  Then, referring to FIGS. 3 and 8, the engaging portion 62 of the main body coupling 61 is fitted into the coupling portion 52 of the developing coupling 41.

  At this time, each of the pair of engaging protrusions 62A of the main body coupling 61 faces each of the pair of engaging portions 54 of the developing coupling 41 in the circumferential direction.

  When the main body coupling 61 is rotated in the clockwise direction when viewed from the left side by the driving force from the motor 63 in the apparatus main body 12, each of the pair of engaging protrusions 62A of the main body coupling 61 is rotated as viewed from the left side. From the upstream in the rotational direction, the pair of engaging surfaces 54A of the developing coupling 41 are brought into contact with each other.

  When the main body coupling 61 rotates in this state, as shown in FIG. 4, the development coupling 41 rotates together with the main body coupling 61 in the clockwise direction when viewed from the left side.

  When the development coupling 41 rotates, the development gear 42, the supply gear 43, and the idle gear 44 rotate counterclockwise as viewed from the left side.

  Then, the developing roller 2 and the supply roller 3 rotate counterclockwise as viewed from the left side.

  When the idle gear 44 is rotated, the agitator gear 45 is rotated clockwise in the left side view.

Then, the agitator 6 rotates clockwise when viewed from the left side.
6). Effect (1) According to the developing cartridge 1, as shown in FIG. 7A, the inner peripheral edge E2 of the fitting portion 53 and the gear portion 51 of the fitting support boss 39 are fitted in the radial direction of the developing coupling 41. An engagement surface 54A is arranged between the outer peripheral edge E1.

  Here, the fitting portion 53 has high rigidity so as to rotate the developing coupling 41 stably. The gear portion 51 has high rigidity so that the driving force received by the development coupling 41 is reliably transmitted to the development gear 42, the supply gear 43 and the idle gear 44.

  Therefore, the rigidity of the entire developing coupling 41 can be ensured by disposing the engaging surface 54A between the fitting portion 53 and the gear portion 51 having such a high rigidity.

  Thus, even when a large driving force is input from the motor 63 of the apparatus main body 12 to the engaging surface 54A via the main body coupling 61, the driving force can be stably received.

As a result, it is possible to efficiently transmit the driving force from the motor 63 of the apparatus main body 12 to the developing roller 2 while suppressing breakage of the developing coupling 41.
(2) According to the developing cartridge 1, as shown in FIG. 6A, the rotation radius R of the gear portion 51 is about four times the radial dimension S of the engagement surface 54A.

Therefore, the engagement surface 54A can be disposed sufficiently away from the central axis A of the development coupling 41, and the driving force received by the engagement surface 54A can be efficiently transmitted to the gear portion 51.
(3) According to the developing cartridge 1, as shown in FIG. 4, the developing coupling 41 overlaps the developing roller 2 when projected in the left-right direction.

Therefore, the development coupling 41 can be arranged efficiently.
(4) According to the developing cartridge 1, as shown in FIG. 7A, the outer peripheral surface of the coupling support boss 39 is located radially outward from the radial inner end edge E4 of the engagement surface 54A. Yes.

  Therefore, the coupling support boss 39 can be arranged so as to overlap the engagement surface 54A when projected in the left-right direction.

  Thereby, the outer diameter of the coupling support boss 39 can be made larger than the outer diameter of the developing coupling 41, and the rigidity of the coupling support boss 39 can be ensured.

As a result, the development coupling 41 can be rotated more stably.
(5) According to this developing cartridge 1, as shown in FIG. 7A, the developing coupling 41 has a gap D between the fitting portion 53 and the gear portion 51.

Therefore, the fitting part 53 and the gear part 51 can be comprised separately, and the fitting part 53 and the gear part 51 can be shape | molded accurately.
(6) According to the developing cartridge 1, the gear portion 51 has gear teeth.

Therefore, the driving force can be transmitted to the developing gear 42, the supply gear 43, and the idle gear 44 with a simple configuration.
7). Modification (1) In the above-described embodiment, the developing roller 2 is cited as an example of the developer carrying member. However, as the developer carrying member, for example, a magnetic roller or a brush roller can be applied.
(2) In the above-described embodiment, the process cartridge 13 includes the drum cartridge 20 and the developing cartridge 21 in a separable manner. However, the process cartridge 13 includes a drum unit having the photosensitive drum 21 and a developing roller 2. The unit may be provided integrally.
(3) In the above-described embodiment, the developing gear 42 directly meshes with the gear portion 51 of the developing coupling 41, but the developing gear 42 is engaged with the gear portion 51 of the developing coupling 41 via a predetermined intermediate gear. May be engaged.

DESCRIPTION OF SYMBOLS 1 Developing cartridge 2 Developing roller 12 Apparatus main body 31 Developing frame 39 Coupling support boss 41 Developing coupling 51 Gear portion 53 Fitting portion 54A Engaging surface 63 Motor A Center axis D Distance E3 Radial outer edge E4 Radial inner edge Edge R Turning radius S Dimensions

Claims (5)

A housing configured to contain developer;
A developer carrier that is rotatably supported by the housing and configured to carry a developer;
A passive member configured to transmit a driving force from an external driving source to the developer carrier, and having a cylindrical shape configured to rotate about an axis along a rotation axis of the developer carrier. A passive member,
The housing includes a support portion that rotatably supports the passive member,
The passive member is
A receiving portion extending along a radial direction of the passive member and configured to receive a driving force from the external driving source;
A transmission unit configured to transmit the driving force received by the receiving unit to the developer carrier, and a transmission unit disposed on an outer peripheral surface of the passive member;
A cylindrical fitting portion that is disposed inward of the transmission portion in the radial direction of the passive member and fits to the support portion so as to be relatively rotatable,
A radially outer end of the receiving portion is located radially inward of the transmitting portion, and is located radially outward of the fitting portion ,
The developing cartridge according to claim 1, wherein the passive member has a gap between the fitting portion and the transmission portion .   2. The developing cartridge according to claim 1, wherein a rotation radius of the transmission portion is at least twice as large as a dimension of the receiving portion in the radial direction.   The developing cartridge according to claim 1, wherein the passive member overlaps the developer carrying member when projected in a direction in which the rotation axis extends.   The outer periphery of the said support part is located in the outward of the said radial direction rather than the inner end part of the said radial direction of the said receiving part, The Claim 1 characterized by the above-mentioned. Development cartridge. The developing cartridge according to claim 1, wherein the transmission unit has gear teeth.

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